Electric traffic-controlling system for railroads.



W. H. LANE A. A. V. T. DAY.

ELECTRIC TRAFFIC GONTROLLING SYSTEM EOE RAILROADS.

APPLIOATON FILED JULYQ. 1908.

1,099,259, Patented June 9,1914.

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UNITED STATES` PATENT OFFICE.

WILLIAM II. LANE', or WEs'rrIELD, NEW` JEItsEY, lANI ALBERT v. T. D'AY, on New incorrette,- NEW YORK, AssIGNoRs, BY MIrsNF. ASSIGNMENTS, To HALL sWIToH a SIGNAL COMPANY, or NEW YORK, N. Y., A coItPoRATIoN or MAINE.

Specification o! Letters Patent.

Patented June 9, 1914.

c Application mea July s, 190e. serial No. 442,769.

To all 'whom it may concern: l Be known'that we, WILLIAM H. LANE and Atnn'r V. T. DAY, citizens of the United States, residing at Westfield, county of Union, and State of New Jersey, and' New Rochelle, in the county ofy Westchester' and State of New York, respectively, have invented a certain new and useful Improvement in Electric Ti'aflic-Controllin Systems for Railroads, of which the following is a specification, reference being-had therein to the accompanying drawings, forming part thereof. j

Our invention relates toV electric traffic controllin systems for railroads of the type in which t e signals or `other traflic-controlling devices are automatically controlled through the action of a train or railway vehicle on a circuit including the track rails.

In some systems of the type referred to it is necessary or desirable, particularly in the case of electric railways, to use continuously conductive' tracky rails' which may serve as conductors for traction current or for other currents, and in such cases, since the several track circuits of the traffic-controlling system cannot be isolated from each other in the ordinary manner by, the interposition of insulated `joints in' .the rails, this isolation of the track circuits must be accomplished in other ways'. l y

' The chief object of the present invention is to produce a. system in which this is accomplished in a novel and effective manner, so that'track circuits formed 1in closely adj acent portions ofthe rails may control their appropriate relays or other electro-responsive apparatus in an eflicient and reliable manner without interference with each other.

One feature of our invention consists in the use. in a system of the type above referred to, of track circuits formed in continuously bonded track rails and including heavy cross-bonds of low resistance and impedance, these cross-bonds being` utilized as members oftransformers by which the alter-l nating or periodic currents in the track circuits operate md'uctively upon the relays controlled thereby.

Another feature of the `invention consists in the use, in conjunction` with such cross.-

bonds, of means ap lied to the track rails between the points o connection of adjacent cross-bonds, to increase the impedance of the rails at these points so as more effectively to confine the currents in the rails to their a propriete paths and thus to more effectively isolate the track circuits.

Other objects and features of the invention will be apparent from the following description of the illustrated embodiment thereof.

We will now describe the embodiment of our invention illustrated in the accompanying drawings, and will thereafter point out the invention in claims.

Figure 1 of the drawings is a diagram of a portion of a block signal system embodying our invention, showing one complete block and portions of the two adjacent blocks. Fig. 2 is a horizontal sectional detail View of one of the track transformers constituting cross-bonds, and Fig. 3 is a vertical section of the same. Fig.' 4 is a side elevation, and Fig. 5i a transverse section, of a Ortion of one of the track rails with impe ance devices applied thereto.

The two signal stations shown in the drawings are desifgnated res ectively as B and C. In the ollowing escription the station next to the right of B, which is not shown, will be called station A. Similar parts of the apparatus at the several stations are designated by similar reference numbers, but in the' description the numbers are followed, where necessary, by letters to indicate at which station the part referred to is located.

The illustrated embodiment of the invention is particularly applicable to electric railroads in which the track rails are used as conductors for traction current, and the drawings represent continuously bonded track rails l suitable for this purpose. The track is divided by the signals into blocks, and at or near the middle of eachblock the rails are connected respectively with the terminals o'f the secondary winding of a transformer 2 energized through transmission wire 3 by a suitable alternating generator 4. Near the right-hand end of each block is' a cross-bond, such as 5 or 5B, and

4 current type. lnet constantly energized by connection,

near the left-hand end is a cross-bond, such as 6 or 6B. The rails and the cross-bonds form a divided track'circuit in each block, which, starting at the transformer terminal connected with one rail, passes in both ,directions through this rail to the cross-bond at the ends of the block, through the crossbonds to the other rail,and back through the lat-terV to the transformer. The track circuits control the signals through the inductive action of the current in the cross-bonds 5, 6. B and 6B. These bonds are short and heavy so as to act eiiiciently as cross-bonds for traction current, but they 4are utilized as the primary windings of transformers of which the secondary windings 7 are connected with relays 8 and `9 at each signal station, and these relays control the line circuits through which the signals are controlled.V

The relays are of the polarized alternating- Each`relay has a vfield magthrough feed wires 10 and 11, with the secondary Winding of a transformer 12 'at each station. The transformers are energized by connection with the -transmission'wires 3. Each relay has a pivoted armature 13 controlling a contact iinger 14 or 15, and the armature is provided With a coil connected with one of the transformer secondaries 7, So long as both field magnet and armature coil are energizedl by currents of the same frequency. and in proper phase relation, the contact finger is maintained in raised position against acoperating iiXed contact; but

y when the armature coil is denergized or energized with current of` opposite' phase, thecontact linger falls and opens the line circuit. v

The line circuit through which the signal at stat-ion B is controlled passes from feed Wire 11C through line wire 20 to signal 19B. thence through contact finger 14 and fixed Contact of relay 8B to line Wire 17 and back f through this line wire to station C, through the fixed contact and contact finger 15 of relay 9C, and thence to feed wire 10. vWith the a parat-us in normal osition, as illustrate this line circuit is`c osed and current from feed-wires 10 and l1 constantlyk energizes the electric operating device of signal 19B, which may be of any ordinary or suitable'character so as to maintain the signal normally cleared. The signal has, however, a normal bias to danger position, and when the line 4circuit is broken by either of therelays 8B or 9C the signal goesat once to danger position.

The action of a train in entering a block is to short-circuit the track circuit. As the train enters theright-hand 'end of the block B-C, it short-circuits the right branch of the circuit and thuscross-bond 5B and relay 8B are denergized, and the line circuit is upon goes to danger position behind the train. When the train reaches the lefthand lportion of the'block, the same condition is maintained through the denergization of relay 9C due to short-circuiting of track current from the cross-bond 6C, the line circuit being held open at relay 9C until the train leaves the block B-Cv. y Y

The isolation of the adjacentv track circuits, comprising cross-bonds such yas 5 and 6 or 5B and 6B, at each station, is effected in two Ways. In the iirst place, the crossbonds are separated from each other by a short distance which is limited by conditions of practice to about thirty (30) feet, but which affords' a length of rail having suiiicient natural iinpedance to cause `the currents to flow by preference through the cross-bonds which are made of negligible-` or small impedance for'this purpose. In other words, the cross-bonds which act as transformer primaries have such a small or negligible resistance and impedance that the current supplied by the transformer of a given block will not 'flow beyondvthe crossbonds at the ends of that block insufficient degree to `interfere with` the proper operation of the system. Thus the transformer cross-bonds have the effect of fixing the limits of their respective blocks or sections and it is this ei'ect or characteristic of the tra-nsformer cross-bonds which. is hereinafter referred to in the expression block limiting or' section limiting .cross-bonds. The latter, although i serving as primary windings in the track transformers, are very short and heavy and are of such low vresistance and impedance thatl each y :bond acts practically as a short circuit with ,respect to the intervening rails and the adjacent `crossbond. In the second place, the short-circuiting action of the bonds on the natural'inr pedance of the interveningpo'rtion of the rails is not depended upon alone, in thepreferred vembodiment of the invention, to accomplish the isolation of the track circuits,

lbut devices areappliedto the rails between the adjacent short-circuiting cross-bonds to increase the impedance ofA theintervening rail portions. v

' In the specific construction of the track transformer shownin Figs. 2'and 3, whichv v1s adapted to be located between'the rails,

the cross-bond 5 consists of a heavybar which makes one turnl and one-half about a laminated iron core 22 of the iron-clad type.I The ends of the .bond are connected.

,directly to the rails and are provided lwith Ielbows 23 to afford sufficient iexibilitv.

. formers,

round the rail, with the exception of rstraight length 5 of square cross-sectionn (as shown in Fig. 3), thence across theend of the core in a short length 5, which tapers from the squarecross-section to the fiat or oblong cross-section of the straight' length j", in which the bond is continuedback through the other channel of thecore to the short length 5' passing acrossthe starting end of the core and tapering back to the square cross-section 5"v (cut away in Fig. 2), which passes again through the core, over the first square length 5, and direct to the opposite terminal elbow. The bonds shown at the signaling station B are slightly diiferent in that they constitute onl a single length of primary conductor in the transassing direct from rail to rail directly t rough the channel of the transformer core which is not separatel illustrated, since it will be substantially t 1e same as the core 22 ofFi 2 and 3 except that the core section 22 gli ig. 3), which incloses the return primary strip 5", will be omitted.

The means for increasing theimpedance of the rails, as shown in Figs. 4 and 5, comprise plates 24 and 25 of iron, which are fastened to the inside and the outside of thc rail by means of bolts 26. These lates surits head, so as to form a substantially complete magnetic circuit about the body of the rail. The plates are applied in short lengths, which may be inserted between the ties upon rails already spiked in place, and they preferably are insulated from the rails sutliciently to prevent diversion of current from the rails to the plates. For this purpose it is, sutlicient to enamel the plates. The current is thus confined to the rails themselves,

and as these are nearly surrounded by iron` magnetic circuits. `their itnpedance is increased to a degree sutlicient to substantially facilitate the operation of the signal apparatus, without, however, substantially im pairing the rails as conductors of traction current, either direct or alternating.

In case, eithercross-:bond at a station should be accidentally broken, the current normally flowing through that bond, as a portion of a track circuit, may be diverted to the adjacent bond, andl it is necessary to provide that such current may not operate to actuate the corresponding, relay 1n the.

`same manner as current from the proper source. To this end the transformers 2 are connected with the rails in opposite sense at alternate blocks. Thus, transformer 2in block AB is connected op ositel to the transformer 2 in block B as s own in the diagram. If cross-bond 6B breaks, current' fom the'transformer in block` A--B may flow through cross-bond 5B.' As this current is opposite in phase tothe current normally flowing inthe crossbond 5B, it actsV to rotate the armature of relay 8B in a directonto open 'the line circuit, andthus to set signal 19B at danger position. If cross-bond 5B breaks, a slmilar action occurs in cross-bond 6B and-relay 9B, thereby .setting the signal at A at danger. a

Various modifications may 'be made ln` the embodiment of the invention hereinbefore described and illustrated in the accompanying drawings, within the nature of the invention and the scope of the following claims.

We claim:

1. A traiiic-controlling system compris ing, in combination with continuously conductive track rails, two transformers of which' the primary windings are connected across the rails, means for energizin with eriodic currents the track circuits ormed y the rails `and'said windin s,-meansfor V increasing the natural impe ance of the. rails between the points of connection of said windings, and electric traffic-controlling means connected with the secondary windings of said transformers.

. 2. `A traffic-controlling system comprising,

Vin combination with continuously conductive track. rails, two transformers of which the primary windings are vconnected across the rails at adjacent points and constitute sectionlimiting cross-bonds of low impedance, means for ener izing with periodic currents the track circuits formed by the railsand said .section-limiting windings, electric traffic-controlling means connected with the secondary windings of said transformers, and means for increasing the natural impedance of the rails between the points ot 4connection of said windings.

3. A trahie-controlling system comprising, in combination with continuouslv conductive track rails. two transformers of which the primary windings are connected across the rails at adjacent points and constitute section-limiting cross-bonds, means for enervgizing with periodic currents of opposite phase the two track circuits formed by the rails and said windings, means for incre-asn ing the natural impedance of the rails between the points of connection of said windn ings, and polarized relays connected with the secondary windings of said transformers.

4. A block signal system comprising, in combination with continuously conductive track rails. transformers of which the pri mary windings are connected across the rails near the ends of the blocks or sections and constitute section-limiting cross-bonds ot low impedance, means for energizing with x A awww@ pmiodo currents the wack Cmu'a fufmesd In msjmny Whww we have axad om by the mils a-d said. Wndngslmeans for signatures in laresnc@ of two Witnesses. increasing the nomm impedance of the mils VYLLAM H. LANE. between the points of cofmecfwzu said ALBERT V. 'R DAY. windings, and signa-Conrolln f relays 00D l Wiznesses: f necte Wsh the seconaxy Wimangs Said K R EL HAMMER,

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